Category Archives: Attribution

Geothermal ocean warming discussion thread

by Judith Curry

“The atmosphere bias of climate science makes it impossible for them to see geological forces and therefore, impossible for them to understand the earth’s climate.” – Thongchai

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Gallery

Extremes

by Judith Curry Politics versus science in attributing extreme weather events to manmade global warming.

Critique of the new Santer et al. (2019) paper

by Ross McKitrick

Ben Santer et al. have a new paper out in Nature Climate Change arguing that with 40 years of satellite data available they can detect the anthropogenic influence in the mid-troposphere at a 5-sigma level of confidence. This, they point out, is the “gold standard” of proof in particle physics, even invoking for comparison the Higgs boson discovery in their Supplementary information.

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Early 20th century global warming

by Judith Curry

A careful look at the early 20th century global warming, which is almost as large as the warming since 1950.  Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming.

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Beyond Milankovitch

by Donald Rapp

On the terminations of Ice Ages.

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Fundamental disagreement about climate change

by Judith Curry

How can the fundamental disagreement about the causes of climate change be most effectively communicated?

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Sea level rise acceleration (or not). Part V: detection & attribution

by Judith Curry

In looking for causes, I have applied the ‘Sherlock Holmes procedure’ of eliminating one suspect after another. The procedure has left us without any good suspect. Thermal expansion was the candidate of choice at the time of the first IPCC review. The computed steric rise is too little, too late, and too linear. – Walter Munk

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What are the main sources of heat that account for the incremental rise in temperature on Earth?

by Judith Curry

Suggestions for the climate ‘red team’ response.

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Will advances in groundwater science force a paradigm shift in sea level rise attribution?

by Jim Steele

 A better accounting of natural groundwater discharge is needed to constrain the range of contributions to sea level rise. The greater the contribution from groundwater discharge, the smaller the adjustments used to amplify contributions from meltwater and thermal expansion.

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The Rise and Fall of Central England Temperatures: Part II

by Tony Brown

This article examines the continued cooling of CET this century

  • Looks at a similar scenario of regional cooling in America
  • Examines CET related urbanisation issues, and the current Met office allowances for this
  • Notes the centuries long general warming of our climate.
  • Notes considerable English seasonal variability over the centuries
  • Examines the key component parts of the weather that affect the British Isles
  • Queries whether wind direction, strength and longevity are major factors in shaping our climate over the centuries.

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Nature Unbound VIII – Modern global warming

by Javier

Summary: Modern Global Warming has been taking place for the past 300 years. It is the last of several multi-century warming periods that have happened during the Neoglacial cooling of the past 3000 years. Analysis of Holocene climate cycles shows that the period 1600-2100 AD should be a period of warming. The evidence suggests that Modern Global Warming is within Holocene variability, but the cryosphere displays a non-cyclical retreat that appears to have undone thousands of years of Neoglacial ice advance. The last 70 out of 300 years of Modern Global Warming are characterized by human-caused, extremely unusual, rapidly increasing CO2 levels. In stark contrast with this rapidly accelerating anthropogenic forcing, global temperature and sea level appear to have continued their rising trend with no perceptible evidence of added acceleration. The evidence supports a higher sensitivity to CO2 in the cryosphere, suggesting a negative feedback by H2O, that prevents CO2 from having the same effect elsewhere.

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Nature Unbound VII – Climate change mechanisms

by Javier

Climate variations that alter the angular momentum of the atmosphere modify the speed of the Earth’s rotation, which affects the length of day (LOD). Alterations in LOD integrate different climate-affecting phenomena, and can anticipate turning points in climate.

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Sea level rise acceleration (or not): Part I – Introduction

by Judith Curry

Introduction and context for a new Climate Etc. series on sea level rise.

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Manufacturing consensus: the early history of the IPCC

by Judith Curry

Short summary: scientists sought political relevance and allowed policy makers to put a big thumb on the scale of the scientific assessment of the attribution of climate change.

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Nature Unbound VI – Centennial to millennial solar cycles

by Javier

Summary: Holocene climate has been affected in different periods by several centennial to millennial solar cycles. The ~ 1000-year Eddy solar cycle seems to have dominated Holocene climate variability between 11,500-4,000 years BP, and in the last two millennia, where it defines the Roman, Medieval, and Modern warm periods. The ~ 208-year de Vries solar cycle displays strong modulation by the ~ 2400-year Bray solar cycle, both in its cosmogenic isotope signature and in its climatic effects. The Centennial, and Pentadecadal solar cycles are observable in the last 400-year sunspot record, and they are responsible for the present extended solar minimum that started in 2008.

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Nature Unbound IV – The 2400-year Bray cycle. Part A

By Javier

The existence of a ~ 2400-year climate cycle, discovered in 1968 by Roger Bray, is supported by abundant evidence from vegetation changes, glacier re-advances, atmospheric changes reflected in alterations in wind patterns, oceanic temperature and salinity changes, drift ice abundance, and changes in precipitation and temperature. This is established with proxy records from many parts of the world.

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Nature Unbound III – Holocene climate variability (Part B)

by Javier

The Neoglacial has been a period of progressive cooling, increasing aridity, and advancing glaciers, culminating in the Little Ice Age. The main Holocene climatic cycle of ~ 2400 years delimits periods of more stable climatic conditions which were identified over a century ago. The stable periods are punctuated by abrupt changes.

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Nature Unbound III: Holocene climate variability (Part A)

by Javier

First in a two part series on Holocene climate variability.

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Nature Unbound II: The Dansgaard- Oeschger Cycle

by Javier

Dansgaard-Oeschger (D-O) events are the most dramatic and frequent abrupt climate change events in the geological record. They are usually explained as the result of an Atlantic Ocean salinity oscillation paced by internal variability. Available evidence however supports that they are the result of an externally paced oceanic-sea ice interaction in the Norwegian Sea. A lunisolar tidal cycle provides an unsupported hypothesis that explains all of the known evidence for the 1470-year pacing and the triggering mechanism for D-O oscillations.

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Prospects for a Prolonged Slowdown in Global Warming in the Early 21st Century

by Nic Lewis

[W]e estimate that the warming slowdown (< 0.1 K/decade trend beginning in 1998) could persist, due to internal variability cooling, through 2020, 2025 or 2030 with probabilities 16%, 11%, and 6%, respectively. – Knutson et al.

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Nature Unbound I: The Glacial Cycle

by Javier

Insights into the debate on whether the Holocene will be long or short.

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What is the relationship between Arctic sea ice decline and Eurasian cold winters?

by Judith Curry

We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. — McCusker et al.

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Dust deposition on ice sheets: a mechanism for termination of ice ages?

by Donald Rapp

In a recent paper, Ellis and Palmer (2016) proposed that deposition of dust on giant ice sheets, thus reducing their albedo, was a principal factor in the termination of Ice Ages over the past 800 kyrs.

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Assessing the causes of early industrial-era warming

by Nic Lewis

Was early onset industrial-era warming anthropogenic, as Abram et al. claim?

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Refocusing the USGCRP

by David Wojick

Our goal here is to begin to articulate a research program into the role of recent long-term natural variability in climate change.

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